/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.engine.trigger.sink.forward.mqtt;

import org.apache.iotdb.db.engine.trigger.sink.api.Handler;
import org.apache.iotdb.db.engine.trigger.sink.exception.SinkException;
import org.apache.iotdb.db.engine.trigger.utils.MQTTConnectionFactory;
import org.apache.iotdb.db.engine.trigger.utils.MQTTConnectionPool;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.List;

public class MQTTForwardHandler implements Handler<MQTTForwardConfiguration, MQTTForwardEvent> {

    private static final Logger LOGGER = LoggerFactory.getLogger(MQTTForwardHandler.class);

    private MQTTConnectionPool connectionPool;
    private MQTTForwardConfiguration config;

    @Override
    public void open(MQTTForwardConfiguration config) throws Exception {
        this.config = config;
        MQTTConnectionFactory factory =
                new MQTTConnectionFactory(
                        config.getHost(),
                        config.getPort(),
                        config.getUsername(),
                        config.getPassword(),
                        config.getConnectAttemptsMax(),
                        config.getReconnectDelay());
        connectionPool =
                MQTTConnectionPool.getInstance(
                        config.getHost(),
                        config.getPort(),
                        config.getUsername(),
                        factory,
                        config.getPoolSize());
    }

    @Override
    public void close() throws Exception {
        connectionPool.clearAndClose();
    }

    @Override
    public void onEvent(MQTTForwardEvent event) throws SinkException {
        try {
            connectionPool.publish(
                    config.getTopic(),
                    ("[" + event.toJsonString() + "]").getBytes(),
                    config.getQos(),
                    config.isRetain());
        } catch (Exception e) {
            if (config.isStopIfException()) {
                throw new SinkException("MQTT Forward Exception", e);
            }
            LOGGER.error("MQTT Forward Exception", e);
        }
    }

    @Override
    public void onEvent(List<MQTTForwardEvent> events) throws SinkException {
        StringBuilder sb = new StringBuilder().append("[");
        for (MQTTForwardEvent event : events) {
            sb.append(event.toJsonString()).append(", ");
        }
        sb.replace(sb.lastIndexOf(", "), sb.length(), "").append("]");
        try {
            connectionPool.publish(
                    config.getTopic(), sb.toString().getBytes(), config.getQos(), config.isRetain());
        } catch (Exception e) {
            if (config.isStopIfException()) {
                throw new SinkException("MQTT Forward Exception", e);
            }
            LOGGER.error("MQTT Forward Exception", e);
        }
    }
}
